Packaging and storage—
Preserve in tight, light-resistant containers. Store at 25
, excursions permitted between 15
and 30
.
Limit of ondansetron related compound D—
Mobile phase—
Prepare a filtered and degassed mixture of 0.02 M monobasic potassium phosphate (previously adjusted with 1 M sodium hydroxide to a pH of 5.4) and acetonitrile (80:20). Make adjustments if necessary (see
System Suitability under
Chromatography 
621
).
Standard solution—
Dissolve an accurately weighed quantity of
USP Ondansetron Related Compound D RS in
Mobile phase, and dilute quantitatively, and stepwise if necessary, with
Mobile phase to obtain a solution having a known concentration of about 0.4 µg per mL.
Test solution—
Transfer about 50 mg of Ondansetron Hydrochloride, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 328-nm detector and a 4.6-mm × 20-cm column that contains packing L10. The flow rate is about 1.5 mL per minute. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention times are about 0.8 for ondansetron related compound C and 1.0 for ondansetron related compound D; and the resolution,
R, between ondansetron related compound C and ondansetron related compound D is not less than 1.5. Chromatograph the
Standard solution, and record the peak responses as directed for
Procedure: the column efficiency determined from the analyte peak is not less than 400 theoretical plates; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of ondansetron related compound D in the portion of Ondansetron Hydrochloride taken by the formula:
10,000(C/W)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Ondansetron Related Compound D RS in the
Standard solution; W is the weight, in mg, of Ondansetron Hydrochloride taken to prepare the
Test solution; and
rU and
rS are the peak areas obtained from the
Test solution and the
Standard solution, respectively: not more than 0.10% is found.
Chromatographic purity—
METHOD I—
Resolution solution—
Dissolve a quantity of
USP Ondansetron Resolution Mixture RS in methanol, and dilute quantitatively, and stepwise if necessary, with methanol to obtain a solution having a known concentration of 12.5 mg per mL.
Standard solutions—
Dissolve an accurately weighed quantity of
USP Ondansetron Hydrochloride RS in methanol, and mix to obtain a solution having a known concentration of about 0.25 mg per mL. Quantitatively dilute this solution with methanol to obtain
Standard solutions, designated below by letter, having the following compositions:
Standard
solution |
Dilution |
Concentration
(µg RS
per mL) |
Percentage
(%, for
comparison
with test
specimen) |
| A |
(1 in 5) |
50 |
0.4 |
| B |
(1 in 10) |
25 |
0.2 |
| C |
(1 in 20) |
12.5 |
0.1 |
Test solution—
Dissolve an accurately weighed quantity of Ondansetron Hydrochloride in methanol to obtain a solution containing 12.5 mg per mL.
Procedure—
Separately apply 20 µL of the
Test solution, 20 µL of each
Standard solution, and 20 µL of the
Resolution solution to a thin-layer chromatographic plate (see
Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Develop the chromatogram in a solvent system consisting of a mixture of chloroform, ethyl acetate, methanol, and ammonium hydroxide (90:50:40:1) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, mark the solvent front, and allow the solvent to evaporate. Examine the plate under short-wavelength UV light: complete resolution of the three components of the
Resolution solution spot is found. Compare the intensities of any secondary spots observed in the chromatogram of the
Test solution with those of the principal spots in the chromatograms of the
Standard solutions: any secondary spot from the chromatogram of the
Test solution having an
RF value corresponding to that of the uppermost secondary spot of the
Resolution solution is not larger or more intense than the principal spot obtained from
Standard solution A (0.4%); and no other secondary spot from the chromatogram of the
Test solution is larger or more intense than the principal spot obtained from
Standard solution B (0.2%).
METHOD II—
Mobile phase and Chromatographic system—
Proceed as directed in the Assay.
Standard solution—
Proceed as directed for Standard preparation in the Assay.
Test solution—
Use the Assay preparation.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the percentage of each impurity in the portion of Ondansetron Hydrochloride taken by the formula:
50,000(C/W)(1/F)(ri / rS),
in which
C is the concentration, in mg per mL, of
USP Ondansetron Hydrochloride RS in the
Standard solution; W is the weight, in mg, of Ondansetron Hydrochloride taken to prepare the
Test solution; F is the relative response factor of the impurities as described in the accompanying table;
ri is the peak area for each impurity in the
Test solution; and
rS is the peak area of ondansetron obtained from the
Standard solution: it meets the requirements given in the accompanying table.
| Compound Name |
Relative Retention Time |
Relative
Response
Factor |
Limit (%) |
Ondansetron related
 compound C |
about 0.32 |
1.2 |
0.2 |
Ondansetron related
compound D* |
about 0.34 |
1.3 |
0.1 |
| Imidazole |
about 0.49 |
0.3 |
0.2 |
| 2-methylimidazole |
about 0.54 |
0.4 |
0.2 |
| Ondansetron |
1.0 |
— |
— |
Ondansetron related
compound A |
about 1.10 |
0.8 |
0.2 |
| Unknown |
— |
1.0 |
0.1 |
| Total |
— |
— |
0.5 |
|
*
Quantified in the test for Limit of ondansetron related compound D.
|
Assay—
Mobile phase—
Prepare a filtered and degassed mixture of 0.02 M monobasic sodium phosphate (previously adjusted with 1 M sodium hydroxide to a pH of 5.4) and acetonitrile (50:50). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Ondansetron Hydrochloride RS in
Mobile phase, and dilute quantitatively, and stepwise if necessary, with
Mobile phase to obtain a solution having a known concentration of about 90 µg per mL.
Assay preparation—
Transfer about 45 mg of Ondansetron Hydrochloride, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix. Pipet 5.0 mL of this solution into a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 216-nm detector and a 4.6-mm × 20-cm column that contains packing L10. The flow rate is about 1.5 mL per minute. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention times are about 1.0 for ondansetron and 1.1 for ondansetron related compound A; and the resolution,
R, between ondansetron related compound A and ondansetron is not less than 1.5. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 1.5%.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C
18H
19N
3O·HCl in the portion of Ondansetron Hydrochloride taken by the formula:
500C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Ondansetron Hydrochloride RS in the
Standard preparation; and
rU and
rS are the peak areas obtained from the
Assay preparation and the
Standard preparation, respectively.
;)
